The structure and shape of the frame of the curtain walls manufactured today in Greece and internationally are based on the traditional structure of the frame with a grid of vertical beams. The vertical beams extend across all the height of the curtain wall as continuous beams. Small horizontal beams transverse and are positioned between the vertical ones. The glassed panels are placed onto this grid in contact both with the vertical and the horizontal elements, and are supported by it.
This structure of the frame has several problems and weaknesses, mainly concerning thermal expansion, antiseismic properties, tightness, safety and operation of the windows, strength and durability of the sealing materials, the general construction cost, etc.